Biomarkers of neurodegeneration across the Global South

Abstract

Research on neurodegenerative diseases has predominantly focused on high-income countries in the Global North. This Series paper describes the state of biomarker evidence for neurodegeneration in the Global South, including Latin America, Africa, and countries in south, east, and southeast Asia. Latin America shows growth in fluid biomarker and neuroimaging research, with notable advancements in genetics. Research in Africa focuses on genetics and cognition but there is a paucity of data on fluid and neuroimaging biomarkers. South and east Asia, particularly India and China, has achieved substantial progress in plasma, neuroimaging, and genetic studies. However, all three regions face several challenges in the form of a lack of harmonisation, insufficient funding, and few comparative studies both within the Global South, and between the Global North and Global South. Other barriers include scarce infrastructure, lack of knowledge centralisation, genetic and cultural diversity, sociocultural stigmas, and restricted access to tools such as PET scans. However, the diverse ethnic, genetic, economic, and cultural backgrounds in the Global South present unique opportunities for bidirectional learning, underscoring the need for global collaboration to enhance the understanding of dementia and brain health.

Figure 1:. Participant distribution in studies included in the selective review per biomarker type across the Global South

Heatmap illustrating the number of participants included in the selected biomarker studies across countries in the Global South. The figure illustrates the included studies across all types of neurodegenerative diseases across the different biomarker types: fluid biomarkers including plasma and CSF (A), cognitive studies (B), neuroimaging studies (C), and genetic studies (D). Due to the large number of controls in some genetic studies, figures for genetic studies exclude number of controls. CSF=cerebrospinal fluid.

Figure 1:. Participant distribution in studies included in the selective review per biomarker type across the Global South

Heatmap illustrating the number of participants included in the selected biomarker studies across countries in the Global South. The figure illustrates the included studies across all types of neurodegenerative diseases across the different biomarker types: fluid biomarkers including plasma and CSF (A), cognitive studies (B), neuroimaging studies (C), and genetic studies (D). Due to the large number of controls in some genetic studies, figures for genetic studies exclude number of controls. CSF=cerebrospinal fluid.

Figure 2:. Multisectoral responses to challenges in biomarker research and potential effects in the Global South

Challenges faced by biomarker research in the Global South and potential solutions are illustrated. Identified challenges such as stigma, validation of biomarkers, infrastructure, and funding require multisectoral solutions across cultural, research, and policy sectors. Suggested research and policy priorities to address these challenges are described. The effects of and potential for biomarker research at a global scale should multiple sectors work together to actualise these priorities are highlighted.